Flip over on the back in stab

Hello!

APM 2.6, fw 3.1.4, F450 frame type X, carbon propeller, anti-vibration on rubber ring
Here is a photo of construction: https://www.dropbox.com/s/bshiuxua3007351/2014-04-23%2023.42.38.jpg

Start flip over on the back (only by roll) and restore to horizontal position during descent.
During “final fall” didn’t react to althold mode.
Loosing control and crash.

Motors and ESC after crash tested on stand and it’s OK.

I’ve found some strange depends between GyrX and Roll in log, but can’t interpret this.
Can someone help investigate this ?

[attachment=0]2014-05-20 11-25-54.zip[/attachment]

One more strange thing!
10709 log line ThrOut is 0 !!!
But ThrOut-0 if I right is mean DisArm, but DisArm status should log too, and I can’t find DisArm in log…

My analysis gives a few issues, one being
COMPASS_OFS_Y = -151
Warning: Compass Offset are not set correctly (-150 to +150 recommended).
Although only slightly out.
http://www.rcgroups.com/forums/showthread.php?t=2151318

Also, possible brown out but this is more likely due to power cut out on impact?
Also, GPS glitch just before the issues started.

Best to download the program to see full results.

Cheers
Kev

Hi Kev!

First of all thank you for your research!
I’ve download program and check my log.

  1. First flip was on about 3700 log line and first GPS glitch only on 9664 line (so this GPS glitch is due to the problems in the air IMHO).
  2. About brown out you are right, is’t just power cut out due meeting with the earth at a 16 m/s speed.
  3. Interest finding about compass offset.

All this info is useful but can’t answer what went wrong.

Here an image that I think important in my situation:
https://dl.dropboxusercontent.com/u/102853/gyr_roll.png

Resonance by GysX before roll.

I think this might be due hardware issue (motors resonance or damping damage) but after roll back to horizon this resonance disappear. After crash I’ve check APM mount and haven’t find any breaking “in flight” elements.
I have no idea why GyrX might be like this.
Maybe APM bug ?

[quote=“bionicbone”]My analysis gives a few issues, one being
COMPASS_OFS_Y = -151
Warning: Compass Offset are not set correctly (-150 to +150 recommended).
Although only slightly out.
http://www.rcgroups.com/forums/showthread.php?t=2151318

Also, possible brown out but this is more likely due to power cut out on impact?
Also, GPS glitch just before the issues started.

Best to download the program to see full results.

Cheers
Kev[/quote]